92 lens high efficiency implosion bomb; used type D pit, composite cores; first weapon with major size/weight reduction over Fat Man; used as primary (1st stage) in the first thermonuclear devices; 4 mods; first weapon to use auto IFI

Similar to MK-24, different secondary; heaviest U.S. nuclear weapon, 2nd highest yield of any U.S. weapon (along with similar Mk-24); 3 mods; Mod 2 contact fused; 1x64 ft. parachute; replaced by the Mk-36

Similar to MK-17, different secondary; heaviest U.S. nuclear weapon, 2nd highest yield of any U.S. weapon (along with similar Mk-17); 2 mods (Mod 2 with contact burst canceled); 1x64 ft parachute; replaced by the Mk-36

Regulus I (SSM-N-8) SSM cruise missile warhead; considered for several other systems all of which were were canceled: the F-101 and B-58 bomb pods, and the Rascal, Regulus II, and Matador cruise missiles

Two-stage TN strategic bomb; Y1 "dirty," Y2 "clean", each in two mods; parachutes 1x5 ft, 1x24 ft ribbon; all Mk-21s converted to Mk-36 in 1957;Retired in favor of Mk-41; at retirement this weapon represented almost half of the megatonnage of the U.S. arsenal

W-37

Warhead

30

900; 940

Canceled Sept 1956

Intended to be a high-yield multipurpose companion to the W-31; XW-37 was redesignated XW-31Y2

Minuteman III/Mk-12A RV warhead; LANL design derived from W-50 with a new lighter primary; part of U.S. "enduring stockpile", but will be removed from active service under START II (to be replaced by W-88s)

Principal Sources:Swords of Armageddon by Chuck Hansen, 1995U.S. Nuclear Weapons: The Secret History by Chuck Hansen, 1988Nuclear Weapons Databook: U.S. Nuclear Forces and Capabilities by Thomas B. Cochran, William M. Arkin, and Milton M. Hoenig, 1984NRDC Nuclear Notebook prepared by Robert S. Norris and William Arkin of the Natural Resources Defense Council, published in The Bulletin of the Atomic Scientists.Especially in issues: